RESUMO
BACKGROUND: Severe peripheral nerve injury leads to skeletal muscle atrophy and impaired limb function that is not sufficiently improved by existing treatments. Fibroblast growth factor 6 (FGF6) is involved in tissue regeneration and is dysregulated in denervated rat muscles. However, the way that FGF6 affects skeletal muscle repair after peripheral nerve injury has not been fully elucidated. METHODS: In this study, we investigated the role of FGF6 in the regeneration of denervated muscles using myoblast cells and an in vivo model of peripheral nerve injury. RESULTS: FGF6 promoted the viability and migration of C2C12 and primary myoblasts in a dose-dependent manner through FGFR1-mediated upregulation of cyclin D1. Low concentrations of FGF6 promoted myoblast differentiation through FGFR4-mediated activation of ERK1/2, which upregulated expression of MyHC, MyoD, and myogenin. FGFR-1, FGFR4, MyoD, and myogenin were not upregulated when FGF6 expression was inhibited in myoblasts by shRNA-mediated knockdown. Injection of FGF6 into denervated rat muscles enhanced the MyHC-IIb muscle fiber phenotype and prevented muscular atrophy. CONCLUSION: These findings indicate that FGF6 reduces skeletal muscle atrophy by relying on the ERK1/2 mechanism and enhances the conversion of slow muscle to fast muscle fibers, thereby promoting functional recovery of regenerated skeletal muscle after innervation.
Assuntos
Fator 6 de Crescimento de Fibroblastos/genética , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/genética , Músculo Esquelético/metabolismo , Traumatismos dos Nervos Periféricos/genética , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Regeneração/genética , Animais , Diferenciação Celular , Linhagem Celular , Movimento Celular , Proliferação de Células , Ciclina D1/genética , Ciclina D1/metabolismo , Fator 6 de Crescimento de Fibroblastos/antagonistas & inibidores , Fator 6 de Crescimento de Fibroblastos/metabolismo , Regulação da Expressão Gênica , Masculino , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Denervação Muscular/métodos , Músculo Esquelético/inervação , Músculo Esquelético/patologia , Proteína MyoD/genética , Proteína MyoD/metabolismo , Mioblastos/metabolismo , Mioblastos/patologia , Miogenina/genética , Miogenina/metabolismo , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Traumatismos dos Nervos Periféricos/metabolismo , Traumatismos dos Nervos Periféricos/patologia , Cultura Primária de Células , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo , Receptor Tipo 4 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 4 de Fator de Crescimento de Fibroblastos/metabolismo , Nervo Isquiático/lesõesRESUMO
We aimed to explore the effects of bromodomain-containing protein 4 (BRD4) inhibition on tumor necrosis factor (TNF)-α-stimulated human rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) behavior and the therapeutic implications using BRD4 inhibitor JQ1 were explored in vivo. The levels of interleukin (IL)-1ß, IL-6, IL-17 and IL-18 in cultural supernatants from TNFα-stimulated RA-FLS were measured by ELISA. RA-FLS migration and invasion in vitro were investigated using wound healing and Matrigel assay. Expression of signaling pathway proteins was measured by Western blot. The in vivo effects of BRD4 inhibitor JQ1 were elucidated using collagen-induced arthritis (CIA) mice. We found BRD4 silencing reduced the secretion of IL-1ß, IL-6, IL-17 and IL-18 from TNFα-stimulated human RA-FLS. Downregulation of BRD4 inhibited FBS-induced migration and invasion of human RA-FLS. BRD4 silencing decreased the phosphorylation of c-Jun and activation of NFκB in TNFα-stimulated RA-FLS. In vivo, BRD4 inhibitor JQ1 reduced the inflammatory response, autoantibody production and joint damage of CIA model. Our data suggest for the first time that BRD4 inhibition has anti-inflammatory property in RA.
Assuntos
Artrite Reumatoide/genética , Artrite Reumatoide/imunologia , Proteínas Nucleares/genética , Fatores de Transcrição/genética , Animais , Apoptose/genética , Artrite Experimental , Artrite Reumatoide/patologia , Autoanticorpos/sangue , Autoanticorpos/imunologia , Azepinas/farmacologia , Proteínas de Ciclo Celular , Movimento Celular/genética , Proliferação de Células , Sobrevivência Celular/genética , Complemento C2/imunologia , Citocinas/sangue , Citocinas/metabolismo , Modelos Animais de Doenças , Expressão Gênica , Marcação de Genes , Humanos , Mediadores da Inflamação/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Camundongos , NF-kappa B/metabolismo , Proteínas Nucleares/antagonistas & inibidores , Interferência de RNA , RNA Interferente Pequeno/genética , Fatores de Transcrição/antagonistas & inibidores , Transfecção , Triazóis/farmacologiaRESUMO
OBJECTIVE: The purpose of this study is to compare the outcomes of intramedullary nailing and plate fixation in the treatment of humeral shaft fractures using meta-analysis. METHODS: PubMed, MEDLINE, EMBASE, the Cochrane Controlled Clinical Trials Register (CCTR) databases were searched for studies that investigated the efficacy of intramedullary nailing and plate fixation in the management of humeral shaft fractures. Delayed healing rate, nonunion, postoperative infection and radial nerve paralysis were key outcomes of interest. Data were searched within the time period of July 1990 through September 2012. The statistical software RevMan 5.0 was used to analyze the statistical significance of the results. RESULTS: Total 459 cases of patients in 10 literature, including 231 cases of plate group and 228 cases of the intramedullary nailing groups were collected. The results of meta-analysis showed that delayed healing rate of humeral shaft fractures was lower in plate fixation compared with intramedullary nailing (RR = 2.64, 95% CI (1.08, 6.49), P < 0.05). No statistically significant difference in nonunion, postoperative infections, radial nerve paralysis and other complications was identified between nailing and plate fixation groups (P > 0.05). CONCLUSIONS: In general, the effect size of intramedullary nailing may be comparable to that of plate fixation in the terms of nonunion, postoperative infections, radial nerve paralysis. The only slightly difference was identified in the event of delayed healing rate.